There is also some example UART code in the stdio demo code included in the AVR libC documenation:
http://www.nongnu.org/avr-libc/user-manual/group__stdiodemo.html
From a larger perspective, if you are not using the Arduino s/w (which it sounds like you aren't)
then the Arduino forums is probably not a good place for getting information/advice.
Head over to the AVRfreaks site: http://www.avrfreaks.net/
for all kinds of good non-Arduino AVR information.
Also, if you are looking at remote controlling AVR i/o from the PC you might want to have a look
at firmata (google around if you aren't familiar with it). That way you put firmata on the AVR and
you can can take control of many of the i/o pin functions from the serial interface.
--- bill